Travel for one for Effectual demand is the amount demanded at the natural price. Market price can deviate from natural price if supply does not equal effectual demand. For example, if too little supply is brought to market, then those who want the product and are able to pay more will bid up the market price. With market price greater than natural price, sellers of the good receive a greater than normal profit. This attracts others to this particular industry, or allows existing producers to pay higher wages and rents to attract new resources. The effect is to increase the supply of the good, driving down the price. When the market price equals the natural price, which occurs when supply equals effectual demand, there is no incentive to change the level of production. Travel for one 2016.